543,697 research outputs found
Seed rain and soil seed banks limit native regeneration within urban forest restoration plantings in Hamilton City, New Zealand
Restoration of native forest vegetation in urban environments may be limited due to isolation from native seed sources and to the prevalence of exotic plant species. To investigate urban seed availability we recorded the composition of seed rain, soil seed banks and vegetation at native forest restoration plantings up to 36 years old in Hamilton City and compared these with naturally regenerating forest within the city and in a nearby rural native forest remnant. Seed rain, soil seed banks (fern spores inclusive) and understorey vegetation in urban forest were found to have higher exotic species richness and lower native species density and richness than rural forest. Both understorey vegetation and soil seed banks of urban sites >20 years old had lower exotic species richness than younger (10–20 years) sites, indicating a developmental threshold that provided some resistance to exotic species establishment. However, the prevalence of exotic species in urban seed rain will allow reinvasion through edge habitat and following disturbance to canopy vegetation. Persistent soil seed banks from both urban and rural sites were dominated by exotic herbaceous species and native fern species, while few other native forest species were found to persist for >1 year in the seed bank. Enrichment planting will be required for those native species with limited dispersal or short-lived seeds, thus improving native seed availability in urban forests as more planted species mature reproductively. Further research into species seed traits and seedling establishment is needed to refine effective management strategies for successful restoration of urban native forests
Growth and population dynamics of crayfish Paranephrops planifrons in streams within native forest and pastoral land uses
Population dynamics of crayfish (Paranephrops planifrons White) in streams draining native forest and pastoral catchments, Waikato, New Zealand, were investigated from September 1996 to July 1998. Crayfish densities were generally greater in native forest streams because of high recruitment over summer, but varied greatly between streams in both land uses. Peak densities in summer were 9 crayfish m-2 in native forest and 6 crayfish m-2 in pasture streams, but peak biomass in summer was much greater in pasture streams. Mark-recapture data showed that crayfish, particularly juveniles, in pasture streams grew faster than in native forest streams, through both greater moult frequency and larger moult increments. Females reached reproductive size at c. 20 mm orbit-carapace length (OCL) after their first year in pasture streams, but after 2 years in native forest streams. Annual degree days >10°C appeared to explain the differences in the timing of life cycles. Estimates of annual crayfish production (range = 0.8-3.4 g dry weight m-2 year-1) were similar in both land uses, and P/B ratios were between 0.95 and 1.2. Despite deforestation and conversion to pasture, crayfish in these Waikato hill-country streams have maintained similar levels of annual production to those in native forest streams, although juvenile growth rates have increased and longevity has decreased
Remnants of the Waikato: native forest survival in a production landscape
This paper addresses the issue of conservation of native biodiversity on privately owned farmland in New Zealand. Based on surveys of Waikato dairy farmers as exemplars of intensive agricultural practice, it examines factors that influence the survival of native forest on land with potential for commercial production. Results suggest that a significant proportion of Waikato dairy farmers regard native forest favourably although the proportion of farmers who actively conserve their native forest is small. Factors that assist the persistence of native forest on dairy farms include personal characteristics of the farmer, past accidents of history which have left forest remnants in place, and physical characteristics of the farm such as topography. While the conservation of native biodiversity within this intensively farmed landscape is strongly influenced by political economy pressures that encourage production, non-utilitarian motives such as aesthetic enjoyment and family heritage can serve to counter the production ethic
Emerging Urban Forests: Opportunities for Promoting the Wild Side of the Urban Green Infrastructure
Many cities aim to increase urban forest cover to benefit residents through the provision of ecosystem services and to promote biodiversity. As a complement to traditional forest plantings, we address opportunities associated with “emerging urban forests” (i.e., spontaneously developing forests in cities) for urban biodiversity conservation. We quantified the area of successional forests and analyzed the species richness of native and alien plants and of invertebrates (carabid beetles, spiders) in emerging forests dominated by alien or native trees, including Robinia pseudoacacia, Acer platanoides, and Betula pendula. Emerging urban forests were revealed as shared habitats of native and alien species. Native species richness was not profoundly affected by the alien (co-)dominance of the canopy. Instead, native and alien plant species richnesses were positively related. Numbers of endangered plants and invertebrates did not differ between native- and alien-dominated forest patches. Patterns of tree regeneration indicate different successional trajectories for novel forest types. We conclude that these forests (i) provide habitats for native and alien species, including some endangered species, (ii) allow city dwellers to experience wild urban nature, and (iii) support arguments for adapting forests to dynamic urban environments. Integrating emerging urban forests into the urban green infrastructure is a promising pathway to sustainable cities and can complement traditional restoration or greening approaches.BMBF, 01LC1501, Bridging in Biodiversity Science (BIBS
Commercial Forestry: An Economic Development Opportunity Consistent with the Property Rights of Wik People to Natural Resources
Wik people on Cape York Peninsula, Queensland, aspire to economic independence. Commercial processing of native forest timbers is seen by Wik people as a culturally appropriate engine for economic development; however, much uncertainty surrounds their property rights to native forest timber. The granting of native title over some traditional Wik land in 2000 and 2004 was seen as a coup by Wik people, but some economists have argued that the inalienable and communal nature of native title is an obstacle to development in indigenous communities. An assessment of Wik property rights to timber resources reveals that a commercial forestry industry is consistent with their rights. In comparison with social and cultural factors, the inalienable and communal characteristics of native title are second-order development constraints for Wik people.native title, native forest management, Aurukun community, Cape York Peninsula.
Differential temporal beta‐diversity patterns of native and non‐native arthropod species in a fragmented native forest landscape
An important factor that hinders the management of non‐native species is a general lack of information regarding the biogeography of non‐natives, and, in particular, their rates of turnover. Here, we address this research gap by analysing differences in temporal beta‐diversity (using both pairwise and multiple‐time dissimilarity metrics) between native and non‐native species, using a novel time‐series dataset of arthropods sampled in native forest fragments in the Azores. We use a null model approach to determine whether temporal beta‐diversity was due to deterministic processes or stochastic colonisation and extinction events, and linear modelling selection to assess the factors driving variation in temporal beta‐diversity between plots. In accordance with our predictions, we found that the temporal beta‐diversity was much greater for non‐native species than for native species, and the null model analyses indicated that the turnover of non‐native species was due to stochastic events. No predictor variables were found to explain the turnover of native or non‐native species. We attribute the greater turnover of non‐native species to source‐sink processes and the close proximity of anthropogenic habitats to the fragmented native forest plots sampled in our study. Thus, our findings point to ways in which the study of turnover can be adapted for future applications in habitat island systems. The implications of this for biodiversity conservation and management are significant. The high rate of stochastic turnover of non‐native species indicates that attempts to simply reduce the populations of non‐native species in situ within native habitats may not be successful. A more efficient management strategy would be to interrupt source‐sink dynamics by improving the harsh boundaries between native and adjacent anthropogenic habitats.Portuguese FCT‐NETBIOME – ISLANDBIODIV grant 0003/2011.info:eu-repo/semantics/publishedVersio
Marked decline in forest-dependent small mammals following habitat loss and fragmentation in an Amazonian deforestation frontier
Agricultural frontier expansion into the Amazon over the last four decades has created million hectares of fragmented forests. While many species undergo local extinctions within remaining forest patches, this may be compensated by native species from neighbouring open-habitat areas potentially invading these patches, particularly as forest habitats become increasingly degraded. Here, we examine the effects of habitat loss, fragmentation and degradation on small mammal assemblages in a southern Amazonian deforestation frontier, while accounting for species-specific degree of forest-dependency. We surveyed small mammals at three continuous forest sites and 19 forest patches of different sizes and degrees of isolation. We further sampled matrix habitats adjacent to forest patches, which allowed us to classify each species according to forest-dependency and generate a community-averaged forest-dependency index for each site. Based on 21,568 trap-nights, we recorded 970 small mammals representing 20 species: 12 forest-dependents, 5 matrix-tolerants and 3 open-habitat specialists. Across the gradient of forest patch size, small mammal assemblages failed to show the typical species-area relationship, but this relationship held true when either species abundance or composition was considered. Species composition was further mediated by community-averaged forest-dependency, so that smaller forest patches were occupied by a lower proportion of forest-dependent rodents and marsupials. Both species richness and abundance increased in less isolated fragments surrounded by structurally simplified matrix habitats (e.g. active or abandoned cattle pastures). While shorter distances between forest patches may favour small mammal abundances, forest area and matrix complexity dictated which species could persist within forest fragments according to their degree of forest-dependency. Small mammal local extinctions in small forest patches within Amazonian deforestation frontiers are therefore likely offset by the incursion of open-habitat species. To preclude the dominance of those species, and consequent losses of native species and associated ecosystem functions, management actions should limit or reduce areas dedicated to pasture, additionally maintaining more structurally complex matrix habitats across fragmented landscapes
Reunion overseas: introduced wild boars and cultivated orange trees interact in the Brazilian Atlantic forest
Little is known concerning novel interactions between species that typically
interact in their native range but, as a consequence of human activity, are also interacting out of their original
distribution under new ecological conditions. Objective: We investigate the interaction between the orange tree
and wild boar, both of which share Asian origins and have been introduced to the Americas (i.e. the overseas).
Methods: Specifically, we assessed whether i) wild boars consume orange (Citrus sinensis) fruits and seeds
in orchards adjacent to a remnant of the Atlantic Forest of Brazil, ii) the orange seeds are viable after passing
through boar’s digestive tract and iii) whether the orange tree may naturalise in the forest remnant assisted by
wild boars. Results: Our camera surveys indicated that wild boar was by far the most frequent consumer of
orange fruits (40.5 % of camera trap-days). A considerable proportion of sown orange seeds extracted from fresh
boar feces emerged seedlings (27.8 %, N = 386) under controlled greenhouse conditions. Further, 37.6 % of sown
seeds (N = 500) in the forest remnant emerged seedlings in July 2015; however, after ~4 years (March 2019)
only 9 seedlings survived (i.e. 4.8 %, N = 188). Finally, 52 sweet orange seedlings were found during surveys
within the forest remnant which is intensively used by wild boars. This study indicates a high potential of boars
to act as effective seed dispersers of the sweet orange. However, harsh competition with native vegetation and
the incidence of lethal diseases, which quickly kill sweet orange trees under non-agricultural conditions, could
seriously limit orange tree establishment in the forest. Conclusions: Our results have important implications not
only because the wild boar could be a vector of potential invasive species, but also because they disperse seeds
of some native species (e.g. the queen palm, Syagrus romanzofiana) in defaunated forests, where large native
seed dispersers are missing; thus, wild boars could exert critical ecological functions lost due to human activityinfo:eu-repo/semantics/publishedVersio
ENVIRONMENTAL VARIABLES ASSOCIATED WITH INVASIVE GLOSSY BUCKTHORN (FRANGULA ALNUS MILL.) AND INDIRECT CONTROL STRATEGIES FOR FOREST MANAGERS
Glossy buckthorn (Frangula alnus Mill.) is one of the most prominent non-native invasive plant species affecting New England forests. It quickly invades a forest and can create a dense understory effectively altering the species composition and dynamics of that forest. To gain a better understanding of the environmental variables associated with glossy buckthorn density we sampled forests across New Hampshire with varying degrees of buckthorn invasion. The effect on tree regeneration was analyzed with measurements of height and abundance of glossy buckthorn and native regeneration. Glossy buckthorn was found to be at its highest densities in disturbed softwood forests that were historically old fields, specifically eastern white pine (Pinus strobus L.), with a thin organic layer and low herbaceous cover on drained loam and clay soils. The data show there is direct competition between glossy buckthorn and forest tree regeneration, although no relationship with regeneration shade tolerance was found. This information was used to create a prescription risk tree to aid forest managers in assessing the risk of buckthorn invasion and inhibition of tree regeneration associated with harvesting and suggests how to adapt their silvicultural prescriptions
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LIST OF FIGURES -- LIST OF TABLES -- PREFACE -- CHAPTER 1— BACKGROUND & OVERVIEW: Alaska’s Native Lands: Alaska Native Claims Settlement Act Lands: Regional Corporations, Village Corporations, Additional ANCSA Land Entitlements, Former Native Reserve Lands; Other Native Lands: Native Allotments, Annette Island Reservation; Native Land Status; Alaskan Forests; What is a Forest Inventory?; Forest Inventories in Alaska; Forest Inventories on Native Land -- CHAPTER 2 — DETERMINING THE NEED FOR AN INVENTORY: Existing Forest Inventory Information; Agency Inventories: Forest Service Inventories, Bureau of Indian Affairs Inventories, Tanana Chiefs Conference Inventories; Level of Inventory -- CHAPTER 3 — INVENTORY PLANNING: Gathering Information; Planning Considerations: Why is This Inventory Needed?, Where will the Inventory Take Place?, What needs to be Inventoried and What Information is to be Collected?, Who is Going to do the Inventory?, When will the Inventory Take Place?, How is the Inventory going to be Done and How will the Data be Processed?, How Much is the Inventory going to Cost?, Unique Alaskan Constraints: Transportation Logistics, Adverse Weather, Musket, Dangerous Wildlife, Vegetation Barriers, Availability of Supplies and Fuel; Advantages of Planning -- CHAPTER 4 — HOW FOREST INVENTORIES ARE CONDUCTED: Maps and Aerial Photographs: Using Aerial Photographs in Forest Inventories, Using Aerial Photographs for Timber Typing; Statistical Considerations of a Forest Inventory: Variability of the Sample, Number of Samples, Sampling Design; Field Measurements: Tree Height, Tree Diameter and Taper, Tree Defects, Tree Age and Growth, Site Conditions, Forestry Equipment -- CHAPTER 5 — AFTER THE FIELD WORK IS DONE: Compilation of Data; When the Inventory is Complete; Looking Toward the Future -- BIBLIOGRAPHY -- APPENDIX I - ALASKA’S PRINCIPAL TREE SPECIES -- APPENDIX II — USES OF ALASKA'S
PRINCIPAL TREE SPECIES -- APPENDIX III — FORESTY CONSULTANTS
IN ALASKA -- APPENDIX IV — TECHNICAL ASSISTANCE DIRECTORY -- APPENDIX V — SAMPLE OUTLINE FOR
DEVELOPING A FOREST
INVENTORY PLAN -- APPENDIX VI — USGS OFFICES IN ALASKA -- APPENDIX VII — NATURAL RESOURCES
SCHOOLS IN ALASK
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